This invention relates to a process for preparing hydroxymethylated homo- or co-polymers of 1,3-dienes.
Low-molecular weight homo- and copolymers of 1,3-dienes have been known for a long time. It is advantageous for many uses to alter the properties of the hydrophobic polymers in a controlled fashion by the introduction of polar groups. One of these groups is the hydroxy group because reactions with isocyanates, for example, can be carried out on such a group.
It has been conventional to form hydroxy groups in low-molecular weight homo- and copolymers of 1,3-dienes by hydrolysis of corresponding epoxy compounds, which can be obtained, for example, according to the process of German Pat. No. 1,173,658. Such a multistage process is, however, expensive and entails additional drawbacks due to the use of compounds that cannot be easily handled (formic acid, hydrogen peroxide).
It is furthermore known to introduce hydroxy groups in the form of hydroxymethyl groups into an unsaturated polymer by hydroformylation of the latter and subsequent hydrogenation of the formyl groups with metal carbonyls (British Pat. No. 1,072,796). Here again, a multistage process is involved wherein relatively expensive catalysts must be utilized.